Cassette of lancet cartridges for sampling blood

ABSTRACT

A cassette containing cartridges for sampling blood from a patient. The cassette includes a container for storing a plurality of cartridges and at least one cartridge in the container. The cartridge includes a cartridge case and a lancet. The lancet has a tip and is housed in the cartridge case. The lancet can be driven to extend the tip outside the cartridge case for lancing the skin of the patient to yield blood. The container has a compartment that contains at least one cartridge. A cartridge from the compartment can be loaded onto a glucometer that drives the lancet in the cartridge to lance the skin of a patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is continuation of commonly assigned, U.S.patent application Ser. No. 09/417,276 filed Oct. 13, 1999 now U.S. Pat.No. 6,472,220, which is a continuation of U.S. patent application Ser.No. 08/985,299 filed Dec. 4, 1997, now issued as U.S. Pat. No.6,036,924. The complete disclosure of all applications listed above areincorporated herein by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates to techniques for obtaining and analyzingblood samples, and more particularly to techniques for storing lancetsthat can be used for obtaining and analyzing blood samples in aconvenient manner.

BACKGROUND

The analysis and quantification of blood components is an importantdiagnostic tool for better understanding the physical condition of apatient. Since adequate noninvasive blood analysis technology is notcurrently available, blood samples still need to be obtained by invasivemethods from a great number of patients every day and analyzed. A wellknown example of such needs is self monitoring of glucose levels by adiabetic individual, e.g., performed at horse. Many products for selfmonitoring of blood glucose levels are available commercially. Upondoctors recommendations and using such products, patients typicallymeasure blood glucose level several (3-5) times a day as a way tomonitor their success in controlling blood sugar levels. For manydiabetics, the failure to test blood glucose regularly may result indamage to tissues and organs, such as kidney failure, blindness,hypertension, and other serious complications. Nevertheless, manydiabetics do not measure their blood glucose regularly. One importantreason is that the existing monitoring products may be complicated,inconvenient, and painful, requiring a pin-prick every time ameasurement is made. Furthermore, these products require some skill,dexterity, and discipline to obtain useful measurements.

Today, a diabetic patient who needs to monitor and control blood glucoselevels typically carries the following paraphernalia: (1) a supply ofdisposable lancets, (2) a reusable lancing device which accepts thelancets, (3) an electronic glucose meter (glucometer), (4) a supply ofdisposable glucose test strips for the meter, and (5) tools for insulininjection (insulin, disposable hypodermic needles, and a syringe). Theseitems may be carried in the form of a kit, which may also contain (6) avariety of control and calibration strips to assure the accuracy of themeter and the measurement. Examples of devices for monitoring bloodglucose include GLUCOMETER ELITE glucose meter, Miles Inc. Elkhart,Ind., and ONE TOUCH PROFILE glucose meter, Lifescan Inc., Milpitas,Calif.

Using a typical glucose meter and lancing device, the sampling andmeasurement process is generally as follows. First, the user preparesthe meter for use by removing a test strip from a protective wrapper orvial and inserting the test strip in the meter. This simple processrequires some dexterity, since the test strips are very small, flexible,and can be damaged by accidentally touching the active sensing region.The glucose meter may confirm the proper placement of the test strip andindicate that it is prepared for a sample. Some glucose meters also mayrequire a calibration or reference step at this time. Next, the patientcleans his finger when he intends to use the lancet—the finger is thepreferred place for routine sampling, because it is an easily accessibleplace for most people. The user prepares the lancing device by (1)removing a cover from the lancing device, (2) placing a disposablelancet in the lancing device, (3) removing a protective shield from thesharp lancet tip, (4) replacing the cover, and (5) setting a spring-likemechanism in the lancing device which provides the force to drive thelancet into the skin. These steps may happen simultaneously, e.g.,typical lancing devices set their spring mechanisms when one installsthe lancet. The user then places the lancing device on the finger. (Thedensity of nerve endings decreases toward the lateral edges of thefingertips; thus, slightly lateral locations are preferred to thefingertips.) After positioning the lancing device on the finger, theuser presses a button or switch on the device to release the lancet. Thespring drives the lancet forward, creating a small wound.

After lancing, a small droplet of blood may appear spontaneously at thelancing site, usually 2-20 .mu.l in volume. If no blood sample appearsspontaneously, the patient may “milk” the finger by massaging orsqueezing it slightly and thereby promoting blood flow from the wound.In either case the user examines the droplet of blood, judges by eye andexperience whether the size of the sample is adequate for the chosentest strip (different test strips require different sample volumes). Ifadequate, the user quickly places the blood sample on a test strip (heldin the glucose meter) according to manufacturer's instructions.Typically, the user inverts the finger to create a pendant drop andtouches the drop (not the finger) to an active region on the test stripthat absorbs the blood. The action is difficult because inverting thefinger over the test strip occludes the view of both the drop and theactive region of the test strip. Furthermore, it is difficult to controlthe separation between the finger and the test strip which may be only amillimeter. Certain types of strip may require blotting and rubbing in aparticular way. Another type of test strip draws the sample into theactive region by capillary action. With this type, the user brings thesample in contact with a small opening on the test strip, and capillaryaction draws the sample volume into the test strip. Both types of strips(absorbent blots and capillaries) require that adequate sample volumesof blood exist on the finger before transferring the sample to thestrip. One cannot apply more drops after the first application. This isbecause the principle of glucose measurement methods using currentglucose meters depends on the rate of change in a chemical reaction, andthe addition of additional sample confounds that rate and thus thecalculation of glucose concentration. For convenience to the patient(user), it is desirable to have the entire droplet wick away from thefinger onto the test strip, leaving the finger mostly free of blood.This is easier to accomplish with the capillary-fill test strips. TheGLUCOMETER ELITE device has capillary-fill type test strips whichrequire a few microliters of sample, only some fraction of whichcontacts the active sensor region.

After blood has been transferred to the test strip, the glucose meterthen measures the blood glucose concentration (typically by chemicalreaction of glucose with reagents on the test strip). Such blood glucosemeasurements permit the diabetic to manage his glucose levels, whetherthat be to inject a corresponding dose of insulin (generally Type Idiabetic) or using a protocol established with his physician to modifyhis diet and exercise (Type I or Type II diabetic). Used lancets andtest strips are removed and discarded (or kept for subsequent disposalin a hazardous waste container kept elsewhere). Any extra blood iscleaned from the equipment and the wound site, and all pieces ofapparatus are stored for future use. The entire process usually takes afew minutes.

With the currently available blood glucose monitoring technology, a newlancet and test strip are used every time. The lancet and test strip areseparate items, often purchased from different manufacturers.Furthermore, both are protected by a package or a protective shield,which must be removed before use, adding the requirement for dexterity.Because both are exposed to blood (considered a bio-hazard) they requirecareful or special disposal.

Each lancet prick causes pain. Among other considerations, pain from thelancet corresponds to the size of the wound, for a given location on thefinger. A small lancet wound, which may cause less pain, may not provideenough blood for a sample, while a large wound may produce considerablepain and may clot slowly, causing great inconvenience to the user, whomust take great care not to smear the leaking blood everywhere—clothes,work surfaces, glucometer, etc.—for some time thereafter.

From the above, it is clear that the conventional technique for bloodsampling and analysis requires dexterity. Dexterity is required to loadstrips in a glucometer (unwrapping and inserting), as well as forpositioning a small droplet onto the sensor surface of a test strip.Sample droplets are a few millimeters across and must be placed onsimilarly sized area of the test strip. This can be especially difficultfor a weak, chronic or elderly diabetic patient, whose motions may beunsteady, vision compromised, or judgment impaired. Thus, the aboveprior systems are inconvenient and unpleasant to use. These shortcomingsreduce the level of compliance of patients who need to perform thesemeasurements assiduously.

Therefore, it is desirable to devise techniques of blood extraction andmeasurement that are easy to administer. What is needed are improveddevices and methods for sampling and analyzing blood that require lessmental concentration, less exertion, and less dexterity.

SUMMARY

This invention provides techniques for extracting a sample of humanblood for the measurement of one or more of its constituents, such asmight be used for routine monitoring of a chronic condition such asdiabetes mellitus. The techniques of the present invention simplify theextraction and transfer of the blood sample, and reduce theinconvenience of the process. The techniques can be advantageously usedin, for example, blood glucose monitoring as explained above.

In one aspect of the present invention, a cassette is provided forstoring cartridges which can be used for sampling blood from the skin ofa patient. The cassette has a cassette housing, i.e., a container, withroom to hold a plurality of cartridges. When in use, the cassettecontains at least one cartridge having a cartridge case and a lancet.The lancet has a tip and is housed in the cartridge case and operativelyconnected to the cartridge case such that the lancet can be driven toextend the tip outside the cartridge case for lancing the skin of thepatient. The container has a compartment for storing at least one, butpreferably many, cartridges. Alternatively many compartments can eachcontain one cartridge. A cartridge can be loaded from the cassette to aglucometer that can drive the lancet to lance the skin of a patient. Inan preferred embodiment the cassette is associated with the driver sothat the driver can be used to drive different cartridges of thecassette without having to remove the cassette from the glucometer. Bykeeping the cartridges, cassette, and the glucometer together, theprocess of lancing the skin is significantly simplified.

In an embodiment of the present invention, the technique of samplingblood utilizes a single unit for lancing and measurement (versusseparate lancers and meters as in methods of prior technology) tosignificantly reduce the assortment of devices and supplies the usermust carry. The glucometer of the present invention can accept apre-loaded number of cartridges (with lancets) that are ready for use.In a preferred embodiment, the lancet and the analysis site for bloodare in the same cartridge, further increasing the convenience of use.Using the blood sampling and analysis devices of the present invention,unlike the procedures used in conventional technology, the long list ofsteps required is significantly reduced. For example, after lancing,there is no need to return the package of lancet and the glucometer tostorage separately. When the time for the next lancing arrives, there isno need to fumble for the lancet, lancing device and glucometerseparately. Furthermore, the cassette can provide a convenient place forstoring spent (i.e. used) cartridges, thereby facilitates easy disposalof spent cartridges and reduces the risk of blood contamination toothers.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to better illustrate the embodimentsof the apparatus and technique of the present invention. In thesefigures, like numerals represent like features in the several views.

FIG. 1A shows an isometric view of an embodiment of the flat type oftest cartridge of the present invention.

FIG. 1B shows a plan view of the test cartridge of FIG. 1A.

FIG. 2 shows an isometric view of another flat type test cartridge ofthe present invention.

FIG. 3A shows an isometric view of a bar-shaped test cartridge of thepresent invention.

FIG. 3B shows an exploded isometric view in portion of the testcartridge of FIG. 3A.

FIG. 3C shows a sectional view along the axis of the bar-shaped testcartridge of the present invention.

FIG. 3D shows a sectional view of the test cartridge of FIGS. 3A-3B,showing the lancet extended for lancing.

FIG. 4A shows a plan side view of a cassette of test cartridges of thepresent invention.

FIG. 4B shows an isometric view of the cassette of FIG. 4A.

FIG. 5A shows an exploded view in portion of a glucometer of the presentinvention, showing a cassette with flat type test cartridges.

FIG. 5B shows a plan view of a glucometer of FIG. 5A.

FIGS. 6A and 6B show an embodiment of a cassette with bar-shapedcartridges.

FIGS. 6C and 6D show another embodiment of a cassette with bar-shapedcartridges.

FIG. 7A shows an embodiment of a cassette for bar-shaped cartridgessuitable for used with a driver nearby.

FIG. 7B shows another embodiment of a cassette for bar-shaped cartridgessuitable for used with a driver nearby.

DETAILED DESCRIPTION

In one aspect of the invention, the present invention provides anapparatus—a cassette of cartridges—that can be used in conjunction witha lancing device that can drive the lancet of a cartridge. The cassettesof the present invention facilitate sampling blood safely, analyzing theblood sample conveniently, and disposing of the lancet and blood safely.In some preferred embodiments, using the lancet device, a patient canperform these sampling and analysis activities without touching thelancet by hand.

Cartridge

Cassettes for holding cartridges can be designed and made for a widevariety of cartridges in accordance with the present invention. Forexample, applicable cartridges include preferred embodiments of testcartridges in the copending U.S. patent application entitled “LancetCartridge for Sampling Blood,”, filed on the same day and commonlyassigned to the same assignee as the present application, are brieflydescribed below. Said copending application is incorporated by referencein its entirety herein. These cartridges are described briefly here. Itis to be understood that although test cartridges with analyticalregions are described in detail herein, the present invention also isapplicable for cartridges that do not have an analytical region, such asa cartridge having a chamber for storing blood after sampling.

An example of a cartridge suitable for use in the present inventionincludes a lancet, a cartridge case with an opening through which thelancet can protrude, and a test area associated to the cartridge casefor analysis of blood. The lancet is mounted in the cartridge case insuch a manner that (1) it can move with respect to the cartridge caseand extend through the opening when forced by a separate actuator, and(2) when no actuating force acts on the cartridge, the lancet has anatural resting position completely inside the cartridge case (forexample, constrained by a detent spring). Analysis can be done in thetest area. An alternative is that a chamber can be used to store bloodto be transferred to a separate analytical area from the test area.Further, it is to be understood that the cassettes of the presentinvention may be modified to accommodate other types of cartridges, andthat other variations of the cassettes can be made to be used with othercartridges show described herein.

Flat Cartridge

FIG. 1A shows an isometric view and FIG. 1B shows a plan view of anembodiment of a test cartridge that can be included in a cassette of thepresent invention. The test cartridge of FIG. 1A and FIG. 1B has agenerally flat appearance, thus allowing many test cartridges to bestacked together for storage in the cassette. However, it is to beunderstood that other non-flat-shaped cartridges can also be used, to solong as they can be stacked. For example, the cartridge can have twoopposite surfaces each having a cross section that is curved, wavy, etc.to match the other surface. A test portion 102 protrudes from one sideof the test cartridge 100. The test cartridge 100 can include a materialfor analysis of blood (see infra). The device 100 is referred to as a“test cartridge” because strips for analysis of blood in prior glucosemeters are called “test strips” in the technical field. The testcartridge 100 has a cartridge case 104 integrally connected with thetest area 102. A lancet 106 is connected to a cantilever lancet frame108. The side of the cantilever lancet frame 108 remote to the lancet106 is affixed to the cartridge case 104 whereas the side of thecantilever frame 108 near the lancet 106 is not affixed to the cartridgecase 104. Thus, the lancet is operatively connected in the cartridgecase 104 for movement. A covering 110 which has an absorbent material(for absorbing residual blood from the wound after lancing and testing)covers a surface (preferably the top surface) of the cartridge case 104.As used herein, the term “top surface” when used in connection with thegenerally flat test cartridge refers to the surface that is exposed forthe most convenient access when the test cartridge is installed inassociation with a driver for lancing. Preferably, the top surface willface the same direction as the display of a glucometer when the testcartridge is loaded (or deployed) in the glucometer. Preferably, thecartridge case has a top face 114 on a top plate 112 and a bottom face116 on a bottom plate 113 that are generally flat such that cartridgesof this kind can be stacked one on top of another, and such that thecovering material 110 can be conveniently used for wiping blood from theskin after lancing.

In this embodiment, as shown in FIG. 1B, the lancet 106 is mounted on atwo-armed cantilever frame 108, the arms 118A, 118B of the cantileverframe 108 being about 20 mm long. A separate mechanism (e.g., anactuator rod not shown in the figures) inserted through a push port (oraccess hole) 120 can push the lancet 106 forward by acting against thepart of the cantilever frame near the blunt end of the lancet 106. Thelancet 106 at its distal end remote from the blunt end has a sharp tip122 for penetrating the skin. As used herein, the term “distal” refersto a location or direction towards the skin during lancing. The term“proximal” refers to a location or direction that is opposite to“distal,” near to the end of the lancet that is attached to thecantilever frame. The cantilever structure causes the lancet 106 to movein a generally straight direction (parallel to the lancet axis) withnegligible curving or sideways motion, in order to pierce the skin withminimal tearing. In an at-rest state the lancet 106 resides about 0.5 mmproximal of the outside surface of the cartridge to prevent unwantedinjuries. The lancet 106 is preferably 0.35 mm in diameter or smaller inorder to not inflict a large wound.

When pushed, i.e., urged forward or actuated, the lancet 106 extendsthrough the cartridge wall through an exit port 133. The lancet 106 willextend out of the distal side distal side of the lancing device throughlancing hole 176, see FIG. 5. The cantilever arms 118A and 118B have aresilient property that, when the cantilever arms are bent, a tensiondevelops to return (or spring) the lancet 106 to its at-rest positionafter lancing the skin and the actuating force on the Lancet 106 iswithdrawn (e.g., the actuator rod that inserts into the port 120withdraws). The cartridge case 104 has a port 120 on the side of thecartridge case near to the blunt end of the lancet 106 for an actuatorarm or rod (e.g., a push rod) to be inserted to push the lancet, therebyextending the lancet tip out the cartridge case 104. The maximal totaltravel of the lancet may be a few millimeters, limited by theinterference (contact) of the cantilever lancet frame 108 and cartridgewall 121. The exact limit of travel of the lancet, which is important tominimize pain and injury, may be controlled by a mechanism which pushesthe cartridge frame (which will be described later in the following).Each cartridge 100 may have an identifying mark 119 on the top surface114 or absorbent cover 110. The identifying mark 119 can indicate thenumber of the cartridge (in a batch) or a special function (e.g., for acalibration cartridge). Further, special function cartridges can have adifferent color.

FIG. 1B is a plan view of the cartridge showing the test portion 102 andthe lancet structure. The test portion 102 includes a test compartment(or test area) 124 depicted as a small square. As used here, the term“test compartment” refers to a space into which blood can pass and inwhich the property of the blood is sensed. A capillary passageway 126,for example, allows communication between a port (or entrance) 128 fromwhich blood enters the test area 124. A vent hole 130 a distance (e.g.,about 5 mm) away from the entrance 128 to the capillary, to the oppositeside of the test area 124, terminates the capillary force to halt thefilling of the capillary volume after pulling a blood sample over theactive test area 124. As an alternative, a compartment withoutanalytical capability can be used in place of a test area for storingblood. Such a compartment may have anticoagulants to prevent the bloodfrom clotting.

In a preferred embodiment (although not clearly shown in FIGS. 1A and1B), the test cartridge 100 has electrical contacts that allow forelectrical communication with an instrument that processes a measurement(and perhaps; controls the sensing) of an analyte (e.g., glucose) on theactive test area. Such electrical contacts can be placed at a variety oflocations on the test cartridge. Placing the contacts on the bottom(i.e., the side facing oppositely from the covering 110) permits asimple design and a simple interface to an instrument.

For analysis of the blood sampled, the test area 124 can containchemicals that react with components of the blood samples. For example,enzymes that react with glucose can be present. The test area may alsocontain reagents that react with the iron present in the bloodhemoglobin. Techniques, including electrochemical or spectroscopictechniques, that can be used for analysis of blood can be incorporatedin the test cartridge 100. Examples of applicable analysis techniquescan be found in, e.g., Tietz, Norbert W., Textbook of ChemicalChemistry, Chapter 6, pp 784-807, W. B. Saunders Co., Philadelphia, Pa.,1986, which are incorporated by reference herein. Test strips foranalyzing glucose, pH, iron, and other common blood qualities are knownin the art. For example, ONE TOUCH PROFILE diabetes tracking systemcommercially available from Lifescan Inc., Milpitas, Calif. 95035 has aunit that utilizes a strip for analyzing blood glucose and has anelectronic system for displaying the result of analysis.

The top plate 112 or the top surface 110 may have a variety of usefulmarkings that indicate which test cartridge is in use (in the case thatthe test cartridge is one out of many from a stack of test cartridges),and indication of batch or lot number of manufacture (for qualitycontrol and calibration), or that the cartridge is a special-purposecartridge (e.g., for checking or calibration). (For comparison, somecurrent lancing systems that make use of calibration strips are, e.g.,GLUCOMETER ELITE glucose meter, Miles Inc. Elkhart, Ind., and ONE TOUCHPROFILE glucose meter, Lifescan Inc., Milpitas, Calif.).

Other embodiments of test cartridges are also applicable in accordancewith the present invention, such as one with the test area 124protruding at the a different side of the lancet area, or having a testarea that resides directly neighboring the lancet 106 near the tip 122,so that the entrance (i.e., sample port) 128 to the capillary volume 126and the exit port 133 for the lancet 106 are nearly coincident. Thislatter design enables the patient to lance the skin, and have the sampleport for the test strip co-located for immediate filling. An example ofsuch an embodiment is shown in FIG. 2. The test cartridge 100C has atest area 124C that is at the immediate vicinity of the lancet exit port133C, which in this embodiment is a hole. The test area 124C can be asensing surface surrounding the lancet exit port 133C. Preferably thetest area 124C is set back slightly from the distal side of thecartridge case 104C so as to avoid inadvertent contact with skin orother objects. When the skin is lanced and a drop of blood appears, thedrop of blood can reach beyond the set back distance to contact the testarea 124C.

Bar-Shaped Cartridge

FIGS. 3A to 3D show an embodiment of a bar-shaped test cartridge thatcan be included in a cassette. The test cartridge has a lancet and ablood analyzer, i.e., sensor (such as a blood chemistry test strip thatcan determine glucose level) and which can be mounted easily into adriving instrument (driver). The overall lancing device operates withthe test cartridge to gather a blood sample in a single operation andsimplifies the measurement procedure. FIG. 3A shows an isometric view ofthe embodiment of the test cartridge 210, about 6 mm in diameter and15-20 mm in length. FIG. 3B shows an isometric view, cut-out in portion,of the test cartridge 210 of FIG. 3A. For comparison, the size and shapeis similar to that of the ULTRAFINE lancets of the Becton-Dickinson Co.It is noted that, although the bar-shaped test cartridge 210 has,preferably, a round cross-sectional shape, it can also have otherregular cross-sectional shapes, such as oval, square, rectangle,rhombus, triangle, etc. An aperture 212 (or lancet exit hole) is locatedat a distal end 714 of the test cartridge 210. A lancet 216 is housed atrest inside the test cartridge 210 proximal of (i.e., beneath ifconsidering the distal end as facing upwards) the aperture 212, whichhas a diameter slightly larger than the lancet 216 (.about.0.35 mmdiameter). The lancet 216 can pass through the aperture 212 whenactuated for lancing. Herein, when referred to a bar-shaped testcartridge, “top,” and “up” refer to a direction or location towards theskin to be lanced, i.e., towards the distal end. The material 218 aroundthe aperture can be an absorbent material which serves to soak up bloodalter lancing. The absorbent material, or the surface beneath it, canalso serve as the active test area 220 for measurements of bloodcharacteristics, such as glucose level. As in existing glucosemeasurement techniques, a chemical reaction occurs when blood contactsthe test area 220, and thus, for example, indicates the presence andamount of glucose. The test area 220 can generate an electrical signalthat is conducted from the test area 220 (preferably via conductorsmolded into the case) to electrical contacts (not shown) on thecartridge case 222. The test cartridge case 222 has a lip 223 protrudingslightly out distally at the distal end 214. The protruding lip 223results in a small void area protecting the test area 220 from beinginadvertently touched. As used herein, the meaning of the term“compartment” when referred to the space for receiving blood also caninclude the space encircled by the lip 223. FIG. 3B is a projectedsectional view in portion of the cartridge, showing the cartridge case222, the lancet 216, and the absorbent material 218 distal to the lancet216 when at rest. The lancet 216 is mounted on a cylindrical lancetmount 224. The cartridge case 222 has a cylindrical internal wall 226upon which the lancet mount 224 can slide.

FIGS. 3C and 3D are sectional views of the test cartridge 210 along theplane C-C of FIG. 3A. Shown in FIGS. 3C and 3D (but not in FIG. 3B forclarity) is a retaining spring 228 which compresses the lancet mount 224against the bottom 230 of the test cartridge 210. A large bore 232 onthe bottom 230 of the cartridge case 222 permits an external actuator(not shown in FIGS. 3A to 3D) to extend through to act on the lancetmount 226. FIG. 3C shows the test cartridge 210 at rest, with the lancet216 residing beneath the aperture 212 and the absorbent surface 218.When an external actuator (not shown) acts through the bottom bore 232against the lancet mount 224, the cartridge spring 228 is compressed andlancet 216 will emerge through the aperture 212 where it can pierce apatient's skin. See FIG. 3D. When the actuator force is removed, e.g.,by withdrawal of the actuator, the resilient nature of the cartridgeretaining spring 228 returns the lancet 216 to the at-rest positioninside the cartridge case 222. In this manner, the lancet 216 is onlyexposed during lancing. Therefore, the user is protected againstunintentionally inflicted wounds and scratches, and also from exposureto the contaminated lancet. With prior technology, accidental lancetpricks can occur more easily.

B. Cassette Containing Several Cartridges.

Cassette For Flat Cartridges

In the embodiment shown in FIGS. 1A and 1B, the cartridge has agenerally thin and flat shape. The thin, flat design of the cartridgespermits several cartridges to be packaged (in a stack) in a smallcassette, similar in design to existing dispensers of single-edged razorblades. A side view of an embodiment of a cassette of test cartridgesaccording to this invention is shown in FIG. 4A. In this figure, thecassette 150 has a container 151 and includes an upper chamber (orcompartment) 152 filled with new (i.e., unused) test cartridges 100ready for use and includes a lower chamber 154 for optional storage ofspent cartridges 158. It is desirable that the spent test cartridge beisolated since it contains blood products. The lower chamber 154 allowsfor efficient, contained disposal of spent test cartridges by the user.A curved spring (160A or 160B) in each chamber holds the test cartridgesin place. The upper spring 160A in the upper chamber 152 also pushes thenew cartridges 100 to the top of the cassette 150 for easy dispensing.The cassette 150 also serves to keep the supply of new test cartridgesclean and properly oriented in anticipation of their use, as well ashelps to maintain the sterility of the test cartridges.

FIG. 4B shows an isometric view of the assembled cassette with an exitport (or opening) 156 on the top surface through which new testcartridges may be ejected. As used herein the term “top” when referringto the cassette means the side with the new test cartridges and wherethe test cartridge next to be deployed is loaded. A sweeper (e.g., withan arm reaching to the end of the top test cartridge 155 in the cassetteremote to the exit port 156 can, with a sweeping motion, push a testcartridge to slide from the stack of new test cartridges out the exitport 156. A practical cassette would hold multiple test cartridges,e.g., 8 to 30 preferably, an adequate supply for 2-7 days, depending onusage. Similarly, the chamber 154 for storing spent test cartridges alsohas an entrance port 161 through which a spent cartridge can be insertedmanually. Preferably, the cassette 150 has a transparent window on theupper half 159 (not shown in FIGS. 4A and 4B) through which the numberof remaining unused cartridges in the cassette can be determined. If theglucometer has a wall that covers the transparent window 159 then thatwall of the glucometer is preferably transparent as well to allow theuser to see the test cartridges in the cassette.

FIG. 5A is an isometric view showing an embodiment of how a cassettecontaining flat test cartridges similar to those described above can beinserted into an instrument (glucometer) that can process the sample anddisplay data. FIG. 5B shows a plan view of the glucometer. In theembodiment shown in FIG. 5A and FIG. 5B, the glucometer 166 has a body168 that has a recess 170 for receiving and securing a cassette 150. Therecess 170 is adjacent to a sweeper 172 that advances individualcartridges into a position for use. As described earlier, the sweeper172 can have a pusher finger that reaches to the end of the top testcartridge 155 in the cassette remote to the exit port 156 and, with asweeping motion, can push the top test cartridge to slide from the stackof new test cartridges out the exit port 156. Alternately, testcartridges may also be loaded individually without a cassette. Thesliding mechanism of the sweeper 172 is similar to a dispenser ofsingle-edged razor blades. The proper, loaded, position results in thetest portion 102 of a test cartridge protruding from the body 168 of theglucometer). The same mechanism can eject the test cartridge after usefor proper disposal.

The body 168 of the glucometer 166 further has electronic circuitsincluding a processor (which is not shown) to control and read theresults of an analysis using the test cartridge, electrical data port173, and control buttons for control, communication, programming, andset-up of the instrument (setting date, time, language preference,scrolling through stored values, on/off settings, instrumentdiagnostics, etc., as well as sending or receiving information toelectronics external to the body).

FIG. 5A also shows a test cartridge 100 in place for use, with thesample port 128 of the cartridge protruding from the glucometer. Asshown in FIG. 5B, the test portion 102 (with the sample port 128 beingmost remote from the body 168) sticks out from the body. Additionally,preferably, a test cartridge is loaded in the body of the glucometersuch that the test cartridge has an exposed top surface (see FIG. 5B).The exposed top of the test cartridge has an absorbent area for wipingexcess blood from the finger if necessary at the end of a test.Furthermore, a mark 178 can be molded or printed into the glucometer toshow the location of the lancet hole 176 (corresponding to the locationof the finger for lancing) through which the lancet will protrude tolance the skin of a patient.

To provide a driving (or actuating) force to push the lancet forlancing, a lockable actuator 180, e.g., one that contains a slidinglever for cocking a spring-activated (the spring and the puncher are notshown) puncher can be used. After cocking the spring in preparation forlancing, a button 182 car be pressed to or release the spring-activatedpuncher to drive the pre-loaded lancet. As a result, the lancet tip isdriven to extend out of the test cartridge 100. Spring actuated cockablemechanisms are know in the art. The present cockable actuator is similarto those found in existing lancing devices, but is integrated into thisinstrument housing. The lancing button 182 preferably is located awayfrom the control buttons 174 and has a different color, and markings,for preventing from being activated inadvertently.

To illustrate the use of the embodiment of the glucometer of FIGS. 5Aand 5B, for example, a test cartridge 100 is loaded (or deployed) in theglucometer 166 and the spring-actuated driver is cocked to get theglucometer ready to lance a finger. When the cocked driver is released,the driver pushes the lancet to lance the finger. After a lancet haspierced the lateral edge of a finger successfully, a convenient way toeduce blood from the wound site is to press gently on the fingertip nearthe wound where the tissue is soft. A gentle push for a second willpromote a few microliters of blood to appear as a stationary droplet (toget a droplet of a 2-20 .mu.l, which is a sufficient sample for glucosemeasurements). With a small wound, the lack of spontaneous bleedingafter testing is also convenient to the patient because no messy,leaking wound remains, which can soil objects or can require protection.Also, the residual scarring is minimal, which is helpful if the patientmust return to the same site later for additional samples—a problem withpatients who make frequent tests.

The droplet of blood can be exposed to sample port 128 and transferredto the test area 124 to be analyzed. Result of the analysis istransferred electrically through electrical contacts, wires, andconnections to the processor. After analysis and data collection, thespent test cartridge can be ejected and stored in the chamber 154 forspent cartridges in the cassette 150.

Cassette For Bar-Shaped Cartridges

FIGS. 6A and 6B shows an embodiment of a cassette of bar-shaped testcartridges of FIGS. 3A to 3D. The cassette 240 has a cartridge holder242, which has a plurality of cavities 244 arranged, here shownlinearly, in each of which a test cartridge 210 can fit. Preferably thedistal portion 243 of the test cartridge 210 fits into the cavity 244snugly. In another embodiment shown in FIGS. 6C and 6D, the cartridgeholder 246 in the cassette 248 is ring-shaped. A cartridge in one ofthese cassettes can be dislodged from the cavity 244 and inserted into alancing device.

In general, a lancing device having a driver with a cocking and releasemechanism including a release button can be used for driving the testcartridge. Such mechanisms with release buttons are known in the art.Examples of a lancing device that can be used in conjunction with thetest cartridges and cassettes of the present invention are described incopending application copending U.S. patent application, entitled“Integrated System and Method for Blood Sampling and Analysis,” andcopending U.S. patent application, entitled “Reproducible Lancing forSampling Blood,” filed on the same day and commonly assigned to the sameassignee as the present application, said copending applications areincorporated by reference in their entirety herein.

FIG. 7A shows an embodiment of a cassette with test cartridges suitablefor use with a driver nearby. In this embodiment of a cassette 302(shown in portion), the test cartridge holder 304 has a plurality ofthroughholes 306 into each of which a test cartridge's 310 proximalportion 312 snugly fits. A driver 305 (shown in portion), is positionedimmediately underneath, i.e., proximal to, the throughhole 306 of testcartridge holder 304 such that the test cartridge 310 can be pushed intothe receiving cavity 307 of the driver 305. When deployed in the driver,the distal portion 314 of the test cartridge 310 still protrudesdistally of the test cartridge holder 304 adequately such that the testcartridge can be conveniently used for lancing. After lancing, an arm ora similar device (not shown) may be used to push the proximal end of thetest cartridge out of the receiving cavity in the driver back intothroughhole 306. Alternatively, a grip (not shown) can be used to pullthe distal portion 314 of the test cartridge 310 back into thethroughhole 306. The test cartridge holder 304 can be linear,ring-shaped, or other shaped so long as it can be maintained in theimmediate vicinity of the driver.

FIG. 7B shows another embodiment of a cassette 320 in which a testcartridge 322 can be slid (i.e., transferred) off the test cartridgeholder 324 into a cartridge holding cavity 326 of a driver 328. Thecartridge holder 324 has a plurality of holding cavities 330 in whichtest cartridges can be stored. On the cartridge holder 324, a side thenormal of which is perpendicular to the axis of the test cartridge 322is open so that a test cartridge 322 can be slid in or out of theholding cavity 330. Similarly, the cartridge holding cavity 326 of thedriver 328 has an open side into which the test cartridge 322 can slideto be held by the driver. The proximal portion 332 of the test cartridge322, the holding cavity 330 of the cartridge holder, and the cartridgeholding cavity 326 of the driver 328 all have planar walls to facilitatethe sliding action of the test cartridge in the cavities. Depressions334 on the side of the planar side walls of the proximal portion 332 ofthe test cartridge 322 can be present to correspond to pins or springson the planar side walls of the cartridge holding cavity 326 of thedriver 328 to help retain the test cartridge 322 therein. The testcartridge 322 can be slid by means of an arm from the cassette 320 tothe driver 328 before lancing. After lancing, the test cartridge 322 isslid back into the cassette 320 before disposal. In the embodiment shownin FIG. 8B, the cassette test cartridge holder 324 is ring-shaped andcan be rotated to position a new test cartridge to face the driver aftera test cartridge has been used.

Although the preferred embodiment of the present invention has beendescribed and illustrated in detail, it is to be understood that aperson skilled in the art can make modifications, especially in size andshapes of features within the scope of the invention.

1. An apparatus for sampling blood from a patient, comprising: a supportmember; a plurality of penetrating members housed in a radial pattern onsaid support member, each of said penetrating members having a tip,wherein the penetrating member can be driven to extend outwardly topenetrate tissue of a patient to yield blood for collection foranalysis; at least one test region receiving said blood for analysis;and wherein each of said penetrating members and said at least one testregion is housed in a cylindrical case, said case being coupled to thesupport member and configured to be coupled to a penetrating memberdriver.
 2. An apparatus for sampling blood from a patient, comprising: asupport member; a plurality of penetrating members housed in a radialpattern on said support member, each of said penetrating members havinga tip, wherein the penetrating member can be driven to extend outwardlyto penetrate tissue of a patient to yield blood for collection foranalysis; at least one test region receiving said blood for analysis;and wherein the support member includes a plurality of slots for holdinga plurality of cases, each case containing at least one penetratingmember and one test region.
 3. An apparatus for sampling blood from apatient, comprising: a support member; a plurality of penetratingmembers housed in a radial pattern on said support member, each of saidpenetrating members having a tip, wherein the penetrating member can bedriven to extend outwardly to penetrate tissue of a patient to yieldblood for collection for analysis: at least one test region receivingsaid blood for analysis; and a calibration cartridge having a functionof calibration or identification of the analytical characteristics ofthe test region.